A method and apparatus are described including assigning sub-channels to different multicast sessions under the assumption that in each session all sub-channels are allocated to all users of that session and power is equally allocated to each sub-channel, then for each session assigning the sub-channels to the users of that session under the assumption that the same amount of power is allocated to each sub-channel, then allocating remaining power to certain sub-channels within the session to increase multicast rate, finally modifying the sub-channel allocations among the multicast sessions depending on the sub-channel and power allocation within each multicast session.